Нижний Новгород, Россия
Нижний Новгород, Россия
Нижний Новгород,, Россия
We have examined the properties of low-frequency electromagnetic waves in multicomponent ionospheric plasma in the 1–30 Hz band, using the magnetoionic theory. Complex permittivity tensor components and refractive indices of normal waves (ordinary and extraordinary) were calculated at altitudes from 80 to 750 km. The calculations show that the refractive indices are highly dependent on frequency and height. Polarization of ordinary and extraordinary waves is elliptical over the entire range of the frequencies investigated. The refractive index and the polarization of normal waves are demonstrated to tend to magnetohydrodynamic (MHD) values only at frequencies lower than 1 Hz. The group velocity vector of an extraordinary wave is not directed along the magnetic field, as follows from the MHD approximation, but it lies inside a cone within ±(5–10) degrees, depending on frequency. The group velocity vector of an ordinary wave is practically independent of the angle with the geomagnetic field as in the MHD approximation. The proposed method for calculating the characteristics of normal waves in the ionosphere can be used to study ULF wave propagation from both natural and artificial ionospheric sources, which arise under the action of powerful HF radio waves in the lower and upper ionosphere.
ULF waves, ionosphere, refractive index, polarization, Alfvén wave, fast magnetosonic wave
1. Alfvén H. Cosmical Electrodynamics. Oxford, Clarendon Press, 1950. 237 p.
2. Aydogdu M., Ozca O. Effect of magnetic declination on refractive index and wave polarization coefficients of electromagnetic waves in mid-latitude ionosphere. Indian J. Radio and Space Phys. 1996, vol. 25, pp. 263-270.
3. Eliasson B., Chang C.-L., Papadopoulos K. Generation of ELF and ULF electromagnetic waves by modulated heating of the ionospheric F2 region. J. Geophys. Res. 2012, vol. 117, no. A10320. DOI:https://doi.org/10.1029/2012JA017935.
4. Ermakova E.N., Kotik D.S., Polyakov S.V., Shchennikov A.V. On a mechanism forming a broadband maximum in the spectrum of background noise at frequencies 2-6 Hz. Radiophysics and Quantum Electronics. 2007, vol. 50, no. 7, pp. 555-569. DOI:https://doi.org/10.1007/s11141-007-0049.
5. Ermakova E.N., Demekhov A.G., Yahnina T., et al. Dynamics of the spectra of multiband Pc1 pulsations in the presence of multiple regions of ion-cyclotron instability in the magnetosphere. Radiophysics and Quantum Electronics. 2019, vol. 62, no.7. DOI:https://doi.org/10.1007/s11141-019-09950-5.
6. Ermakova E.N., Ryabov A.V., Kotik D.S. Influence of geomagnetic activity variations on polarization spectra of ULF magnetic noise based on ground-based monitoring data. Proc. XXVII All-Russian Open Scientific Conference “Propagation of Radio Waves”. Kaliningrad, 2021, pp. 269-274.
7. Ermakova E.N., Kotik D.S., Ryabov A.V. Characteristics of ULF magnetic fields in the 3D inhomogeneous Earth -ionosphere waveguide. J. Geophys. Res.: Space Phys. 2022, vol. 127, no. 3. DOI:https://doi.org/10.1029/2021JA030025.
8. Fatkullin M.N., Zelenova T.I., Kozlov V.K., Legen’ka D., Soboleva T.N. Empirical Models of the Mid-Latitude Ionosphere. Moscow, Nauka Publ., 1981. 256 p. (In Russian).
9. Fujita S. Duct propagation of a short-period hydromagnetic wave based on the international reference ionosphere model. Planetary Space Sci. 1987, vol. 35, no. 91, pp. 91-103. DOI:https://doi.org/10.1016/0032-0633(87)90148-6.
10. Fujita S. Duct propagation of hydromagnetic waves in the upper ionosphere. Dispersion characteristics and loss mechanism. J. Geophys. Res. 1988, vol. 93, no. A12, pp. 14674-14682. DOI:https://doi.org/10.1029/JA093iA12p14674.
11. Ginzburg V.L. The Propagation of Electromagnetic Waves in Plasmas. Oxford, NewYork, Pergamon Press, 1970, 615 p.
12. Ginzburg V.L., Rukhadze A.A. Waves in Magnetoplasma. Handbook Elektrophys. Springer Verlag, 1972. 216 p.
13. Gintzburg M. A. Low-frequency waves in multicomponent plasma. Geomagnetism and Aeronomy. 1963, no.3, pp. 610-614, (In Russian).
14. Greifinger C., Greifinger S. Theory of hydromagnetic propagation in the ionospheric waveguide. J. Geophys. Res. 1968, vol. 73, no. 23. pp. 7473-7490.
15. Helliwell R. Whistlers and Related Ionospheric Phenomena. Stanford University Press, 1965.
16. Jacobs J.A., Watanabe T. Propagation of hydromagnetic waves in the lower exosphere and the origin of short period geomagnetic pulsations. J. Atmos. Terr. Phys. 1962, vol. 24, pp. 413-419.
17. Kotik D.S., A.V. Ryabov, E.N. Ermakova et al. Properties of the ULF/VLF !!?signals generated by the SURA facility in the upper ionosphere. Radiophysics and Quantum Electronics. 2013, vol. 56, no. 6. pp. 344-354. DOI:https://doi.org/10.1007/s11141-013-9438-9.
18. Kotik D.S., Ryabov A.V., Yashnov V.A., Orlova E.V. Propagation of ULF radiation from an artificial ionospheric source in a 3D inhomogeneous MHD waveguide. Radiophysics and Quantum Electronics. 2021, vol. 64, no. 1, pp. 1-10. DOI:https://doi.org/10.1007/s11141-021-10107-6.
19. Lysak R.L., Waters C.L., Sciffer M.D. Modeling of the ionospheric Alfvén resonator in dipolar geometry. J. Geophys. Res. Space Phys. 2013, vol. 118, no. 4, pp. 1514-1528. DOI:https://doi.org/10.1002/jgra.50090.
20. Polyakov S.V., Rapoport V.O. The ionospheric Alfvén resonator. Geomagnetism and Aeronomy. 1981, vol. 21, pp. 816-822 (In Russian).
21. Singh A. K, Narayan D., Singh R.P. Propagation of extremely low frequency waves through the ionosphere. Earth, Moon and Planets. 2002, vol. 91, pp. 161-179. DOI: 10.1023/ A:1022420426950.
22. Vavilov D.I., Shklyar D.R. Wave effects related to altitude variations in the ion composition of the ionosphere. Radiophysics and Quantum Electronics. 2016, vol. 59, no. 7. pp. 519-534. DOI:https://doi.org/10.1007/s11141-016-9720-8.
23. Whang Y. C. Attenuation of magnetohydrodynamic waves. Astronomical J. 1997, vol. 485, no.1 pp. 389-397.
24. Yeşil A., Sağir S. Updating conductivity tensor of cold and warm plasma for equatorial ionosphere F2-region in the Northern Hemisphere. Iranian J. Science and Technology. Transaction A. 2019, vol. 43, no. 5, pp. 315-320. DOI:https://doi.org/10.1007/s40995-017-0408-5.
25. URL: https://ccmc.gsfc.nasa.gov/modelweb/models/iri2016_vitmo.php (accessed December 14, 2022).
26. URL: https://ccmc.gsfc.nasa.gov/modelweb/models/msis_vitmo.php (accessed December 14, 2022).
27. URL:https://ccmc.gsfc.nasa.gov/modelweb/models/igrf_vitmo.php(accessed December 14, 2022).
